chore: add demo banner (#1739)

web/src/components/DemoBanner.tsx

@@ -0,0 +1,38 @@
+import { useEffect, useState } from "react";
+import { useGlobalStore } from "@/store/module";
+import Icon from "./Icon";
+
+interface State {
+  show: boolean;
+}
+
+const DemoBanner: React.FC = () => {
+  const globalStore = useGlobalStore();
+  const profile = globalStore.state.systemStatus.profile;
+  const [state, setState] = useState<State>({
+    show: false,
+  });
+
+  useEffect(() => {
+    const isDemo = profile.mode === "demo";
+    setState({
+      show: isDemo,
+    });
+  }, []);
+
+  if (!state.show) return null;
+
+  return (
+    <div className="flex flex-row items-center justify-center w-full py-2 text-lg font-medium dark:text-gray-300 bg-white dark:bg-zinc-700 shadow">
+      <div className="w-full max-w-6xl px-4 flex flex-row justify-between items-center gap-x-3">
+        <span>A lightweight, self-hosted memo hub. Open Source and Free forever.</span>
+        <a className="btn-primary shadow" href="https://usememos.com/docs/install/docker" target="_blank">
+          Install
+          <Icon.ExternalLink className="w-4 h-auto ml-1" />
+        </a>
+      </div>
+    </div>
+  );
+};
+
+export default DemoBanner;